Evaporative cooling system wont start

The system was installed Nov 2006 and has worked just fine. Yesterday was the first hot day and when I got home in the evening I turned it on and nothing happened. I changed batteries in the control. I opened the ceiling access and there is no sound of electronic solenoids or anything operating when I use the remote control. I climbed on the roof and got rid of twigs that looked like a birds next. I took off one side panel. Inside was clean and clear but completely dry. The valve handle for water supply is on.

The section of the house where the unit is located is two stories up. So appropriate safety gear will be needed. Roof access is easy as block is sloping and front is single storey. The roof is a pitched roof with steel colorbond